(1) Field of the Invention
This invention relates generally to communications and, more particularly, to satellite broadcast systems.
(2) Background
A proposed satellite digital audio radio system (SDARS) supports multiple audio and data program channels (program channels) for broadcasting CD-like music and talk shows to mobile and fixed receivers. Illustratively, the system provides for the transmission of 100 program channels.
Consequently, there is desired a transmission frame structure for efficient transport of these channels.
A transmission frame structure is presented for a satellite digital audio radio system (SDARS). An SDARS transmitter processes N program channels into M clusters of program channels, each cluster representing k program channels, where M greater than 1, k greater than 1, and (M)(k)xe2x89xa6N. The SDARS transmitter transmits a transmission signal representing the M clusters and including cluster synchronization information for each cluster such that the cluster synchronization information for each cluster is identical.
In an embodiment of the invention, a satellite digital audio radio system (SDARS) uses one identical maximal length PN (pseudo-random number) sequence as a cluster synchronization word for five clusters. The relative phases of five cluster correlation results is used by a receiver to uniquely identify each individual cluster.
In accordance with a feature of the invention, the above-mentioned five correlation results are combined to improve performance.